| |
| package com.trilead.ssh2.util; |
| |
| import com.trilead.ssh2.log.Logger; |
| |
| import java.io.PrintWriter; |
| import java.io.StringWriter; |
| import java.util.Collections; |
| import java.util.LinkedList; |
| |
| |
| /** |
| * TimeoutService (beta). Here you can register a timeout. |
| * <p> |
| * Implemented having large scale programs in mind: if you open many concurrent SSH connections |
| * that rely on timeouts, then there will be only one timeout thread. Once all timeouts |
| * have expired/are cancelled, the thread will (sooner or later) exit. |
| * Only after new timeouts arrive a new thread (singleton) will be instantiated. |
| * |
| * @author Christian Plattner, plattner@trilead.com |
| * @version $Id: TimeoutService.java,v 1.1 2007/10/15 12:49:57 cplattne Exp $ |
| */ |
| public class TimeoutService |
| { |
| private static final Logger log = Logger.getLogger(TimeoutService.class); |
| |
| public static class TimeoutToken implements Comparable |
| { |
| private long runTime; |
| private Runnable handler; |
| |
| private TimeoutToken(long runTime, Runnable handler) |
| { |
| this.runTime = runTime; |
| this.handler = handler; |
| } |
| |
| public int compareTo(Object o) |
| { |
| TimeoutToken t = (TimeoutToken) o; |
| if (runTime > t.runTime) |
| return 1; |
| if (runTime == t.runTime) |
| return 0; |
| return -1; |
| } |
| } |
| |
| private static class TimeoutThread extends Thread |
| { |
| public void run() |
| { |
| synchronized (todolist) |
| { |
| while (true) |
| { |
| if (todolist.size() == 0) |
| { |
| timeoutThread = null; |
| return; |
| } |
| |
| long now = System.currentTimeMillis(); |
| |
| TimeoutToken tt = (TimeoutToken) todolist.getFirst(); |
| |
| if (tt.runTime > now) |
| { |
| /* Not ready yet, sleep a little bit */ |
| |
| try |
| { |
| todolist.wait(tt.runTime - now); |
| } |
| catch (InterruptedException e) |
| { |
| } |
| |
| /* We cannot simply go on, since it could be that the token |
| * was removed (cancelled) or another one has been inserted in |
| * the meantime. |
| */ |
| |
| continue; |
| } |
| |
| todolist.removeFirst(); |
| |
| try |
| { |
| tt.handler.run(); |
| } |
| catch (Exception e) |
| { |
| StringWriter sw = new StringWriter(); |
| e.printStackTrace(new PrintWriter(sw)); |
| log.log(20, "Exeception in Timeout handler:" + e.getMessage() + "(" + sw.toString() + ")"); |
| } |
| } |
| } |
| } |
| } |
| |
| /* The list object is also used for locking purposes */ |
| private static final LinkedList todolist = new LinkedList(); |
| |
| private static Thread timeoutThread = null; |
| |
| /** |
| * It is assumed that the passed handler will not execute for a long time. |
| * |
| * @param runTime |
| * @param handler |
| * @return a TimeoutToken that can be used to cancel the timeout. |
| */ |
| public static final TimeoutToken addTimeoutHandler(long runTime, Runnable handler) |
| { |
| TimeoutToken token = new TimeoutToken(runTime, handler); |
| |
| synchronized (todolist) |
| { |
| todolist.add(token); |
| Collections.sort(todolist); |
| |
| if (timeoutThread != null) |
| timeoutThread.interrupt(); |
| else |
| { |
| timeoutThread = new TimeoutThread(); |
| timeoutThread.setDaemon(true); |
| timeoutThread.start(); |
| } |
| } |
| |
| return token; |
| } |
| |
| public static final void cancelTimeoutHandler(TimeoutToken token) |
| { |
| synchronized (todolist) |
| { |
| todolist.remove(token); |
| |
| if (timeoutThread != null) |
| timeoutThread.interrupt(); |
| } |
| } |
| |
| } |